DHS has issued a [1] Worksite Enforcement Fact Sheet and  [2] Worksite Enforcement Case Examples.

Employers who have undocumented people working for them should seek legal advice on how to handle the situation in light of the enforcement-heavy approach the government is taking.  Balancing the safe-harbor provisions required by immigration law with anti-discrimination and wrongful termination statutes could prove tricky.  Moreover, no-match letters issued in error could become a nightmare for many employers and US Citizens.  I am sure we will hear many reports of how this all plays out in the coming months.